Looks like Intel's new and latest bios for DH87MC addresses this issue:
motherboard: Intel DH87MC
bios: MCH8710H.86A.0152.2013.1104.2159
processor: Intel Core i7-4771
ram: 32GB (corsair CML16GXM2A1600C9 4x8GB)
addon-1: Renesas USB 3.0 PCIx (D720202)
addon-2: ADS Tech NEC USB 2.0 PCI (D720101GJ) -- USBIF certified
os: Windows 8.1 Enterprise 64bit
With new BIOS, Windows 8.1 Enterprise 64bit OS is booting fine with no hang up problem with NEC USB 2.0 PCI card inserted. Finally 
On to my next task -- see if I can use this machine as a WHCK Client (crossing my fingers).